--my userX is g, and /usr/bin/sbcl is path to steel bank common lisp (switch to clisp or CMU lisp if you like, which are other great common lisp implementations)

--then save [:wq], and [emacs & enter] to launch emacs, [ALT-x slime -return-] to enter slime mode, which takes like 10s to load, and there you are a nice working lisp dev environment. Emacs has its own tutorial built in and www.sbcl.org has info on sbcl..enjoy..